1. Field of the Invention
The present invention relates to means for fastening, disassembling, clamping or connecting a hand tool, and more particularly to a small outer diameter quick release extension rod.
2. Description of the Prior Art
Extension rod is one of very common tools in hand tool industry. To facilitate replacing a tool head B, a conventional extension rod A is normally used together with a positioning-controlling structure 10. As shown in FIG. 1, the extension rod A is inserted in one end of an inner rod 11, and the other end of the inner rod 11 is connected to the too head B. A slide sleeve 12 is mounted on the inner rod 11 and includes a notch 121 in an inner surface thereof facing the inner rod 11. In the notch 121 is movably disposed a positioning steel ball 13. Under normal condition, the notch 121 of the slide sleeve 12 is misaligned with the positioning steel ball 13 in such a manner that the slide sleeve 12 is pressed against the positioning steel ball 13, and the positioning steel ball 13 presses against the tool head B to keep the tool head B in a fixed position. When the slide sleeve 12 elastically moves relative to the inner rod 11 to align the notch 121 of the slide sleeve 12 with the positioning steel ball 13, the positioning steel ball 13 will slide into the notch 121 of the slide sleeve 12, releasing the tool head B.
However, as known from the above structural relationship, to achieve the effect of positioning and controlling, the conventional extension rod should employ the inner rod 11 and the slide sleeve 12 together. For the same reason, the outer diameter of the positioning-controlling structure is increased, which leads to a certain degree of difference between the outer diameters of the extension rod A, the tool head B and the positioning-controlling structure 10, causing much inconvenience in use. In addition, since the positioning-controlling structure 10 must include the inner rod 11 and the slide sleeve 12, the weight of the positioning-controlling structure 10 is also increased. When a drive tool is used to drive the extension rod A, much more energy will be wasted.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.